Re: [asa] Physical Model for Climate

On 2/22/07, Rich Blinne <rich.blinne@gmail.com> wrote:
>
>
> On Feb 22, 2007, at 5:14 AM, Dave Wallace wrote:
>
> The March 2007 edition of Scientific American page 71 shows a picture of
> a "RIVER MODEL at the National Center for Earth Dynamics". The
> constructed model is being used to study how sediments move in rivers. I
> seem to recall that other such physical models of rivers have been
> constructed. At first thought it would seem improbable that any
> reasonably sized scale model of a river could result in useful data. I
> suspect they also use digital models to aid their understanding of sediment
> flows.
>
>
> Have any physical models been attempted for climate? If so what results?
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>
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> Yes and this is the fundamental reason why we are very confident of the
> amount of forcing by GHG. The forcings by the greenhouse gases have little
> uncertainty because their concentrations are accurately measured in the
> atmosphere, and their infrared absorption properties are very accurately
> measured in the laboratory (your physical model). The two are put together
> using highly accurate numerical methods that have little error.
>
>
>
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> The effect [CO2] has on the planet's radiation balance is now measurable.
> In 2001, Helen Brindley, an atmospheric physicist at Imperial College
> Longon, examined satellite data over almost three decades to plot changes in
> the amount of infrared radiation escaping from the atmosphere into space.
> Because what does not escape must remain, heating Earth, this is effectively
> a measure of how much heat is being trapped by greenhouse gases -- the
> greenhouse effect. In the part of the infrared spectrum trapped by carbon
> dioxide -- wavelengths between 13 and 19 micrometers -- she found that less
> and less radiation is escaping. The results for the other greenhouse gases
> were similar.
>